Supporting navigation through video content delivered via adaptive streaming is technically challenging; particularly if the goal is to provide high quality visual feedback of the content during high-speed navigation. Network bandwidth constraints and decoder limitations make it impractical to increase playback speed as the primary mechanism to support high-speed navigation. A variety of alternative solutions have attempted to support navigation with some form of visual feedback, but none provides a user experience that approaches the visual fidelity that can be achieved using the analogous navigation functions of, for example, a DVD or Blu-ray Disc player.
One approach generates image files (e.g., JPEG files) of video frames selected from the source video at fixed intervals. These files are then made available for random access, e.g., by “scrubbing” through a visual timeline. In addition to being duplicative of the original content, these image files use an inefficient data format and typically have a lower image quality than the native video format. Moreover, the arbitrary selection of frames at fixed intervals often results in many of the images not being useful for the intended purpose. For example, arbitrarily selected frames might correspond to a fade between scenes and therefore may not contain much if any useful visual information. A similar approach uses frames selected from the source video as the display images for navigation. This is more efficient than generating additional image files but, because these frames are selected at fixed intervals, the displayed images may still not correlate with useful frames.
An alternative class of solutions allows a user to skip ahead or back to preselected locations in video content, e.g., the beginning of a chapter, a commercial break, or an arbitrary time interval. However, as will be appreciated, such approaches are not well suited for enabling a user to navigate to a precise point in a video.